Recent innovations in passenger transportation systems associated with buildings have included horizontally transferring elevator cabs between elevator car frames and horizontal transport bogies, as well as between car frames or bogies and loading/unloading platforms, such as passenger lobbies.
In larger systems, a number of passenger or freight cabs may be transported horizontally on corresponding bogies arranged end-to-end in a train, either to travel large distances within a single building, or more particularly, to transfer distances between different buildings of the same system.